1. Field of the Invention
This invention relates to novel crystalline porous tectosilicates, sometimes hereinafter referred to as porotektosilicates, constituting unobvious intermediates of two known zeolites to yield unique products, to methods for their preparation and to organic compound conversion, especially hydrocarbon conversion, therewith.
2. Discussion of the Prior Art
Zeolite materials, both natural and synthetic, have been demonstrated in the past to have catalytic capabilities for various types of organic compound conversion. Certain zeolitic materials are ordered porous crystalline aluminosilicates having a definite crystalline structure within which there a large number of cavities and channels, which are precisely uniform in size. Since the dimensions of these pores are such as to accept for adsorption molecules of certain dimensions while rejecting those of larger dimensions, these materials have been referred to as "molecular sieves" and are utilized in a variety of ways to take advantage of these properties.
Such molecular sieves include a wide variety of positive ion-containing crystalline aluminosilicates, both natural and synthetic. These aluminosilicates can be described as a rigid three-dimensional network of SiO.sub.4 and AlO.sub.4 in which the tetrahedra are cross-linked by the sharing of oxygen atoms whereby the ratio of the total aluminum and silicon atoms to oxygen is 1:2. The electrovalence of the tetrahedra-containing aluminum is balanced by the inclusion in the crystal of a cation, for example an alkali metal or an alkaline earth metal cation. This can be expressed by formula wherein the ratio of Al to the number of various cations, such as Ca/2, Sr/2, Na, K or Li is equal to unity. One type of cation may be exchanged either in entirety or partially by another type of cation utilizing ion exchange techniques in a conventional manner. By means of such cation exchange, it has been possible to vary the size of the pores in the given aluminosilicate by suitable selection of the particular cation. The spaces between the tetrahedra are occupied by molecules of water prior to dehydration.
Prior art techniques have resulted in the formation of a considerable number of synthetic crystalline aluminosilicates, among which are zeolite ZSM-5 described in U.S. Pat. No. 3,702,886, the entire contents of which are incorporated herein by reference and ZSM-11 described in U.S. Pat. No. 3,709,979, the entire contents of which are incorporated herein by reference. Both of the aforenoted zeolites, i.e., ZSM-5 and ZSM-11, are characterized by a unit cell parameter, hereinafter described in detail, of about 20 Angstrom units.